On many portable electronics with tactile button interfaces, there is a need to have the surface of the button as close to flush as possible with the surface of the housing in which it sits. This is exemplified in the current line of iPod™ products made by Apple Computer Inc., of Cupertino, Calif., which have scroll wheel interfaces. Scroll wheel interfaces permit a user to run a finger around the wheel to navigate through menus. Because dome switches beneath the surface of the wheel can be actuated when pushed intentionally by the user, there is an assembly tolerance gap between the dome switch and its actuator.
As a result of this gap, there can be a small amount of “play” in the fit of the wheel to the housing. This “play” can have a negative impact on the feel of the device. It would therefore be desirable to reduce the gap by having the wheel justified toward the face of the product. It would also be desirable to implement this reduction via a separate mechanism from the dome switches beneath the scroll wheel.
In addition, other product designs may be implemented with a silicone sheet directly behind the wheel and the housing. The silicone sheet can help to keep the two planes flush. However a need exists for a more efficient system for maintaining the two planes substantially, consistently flush.